A method and apparatus for determining a position of a well casing support

Abstract

The present application belongs to the field of oil production engineering in petroleum industry, and particularly relates to a method and device for determining the support position of oil well casing, aiming at solving the problem of how to determine the support position of oil well casing. The present application comprises: stopping the work of the pumping unit, parking the pumping unit at the top dead center, cutting off the production pipeline and emptying the pressure, and cutting the production pipeline to release the stress; installing the device for determining the support position of oil well casing on the wellhead of the oil well, and calculating the support force; placing two load sensor pads on the bottom surface directly below the pipelines on both sides of the large four-way cross, and placing two jacks on the two load sensor pads respectively; lifting the two jacks at the same time, and stopping lifting the two jacks when the support force displayed on the load sensor pads reaches the calculated support force; rotating the lifting nut until the large four-way cross bottom flange surface is tightened, and then re-welding the production pipeline. The present application accurately determines the support position and support force.

Description

Technical Field

[0001] This invention belongs to the field of oil production engineering in the petroleum industry, and specifically relates to a method and device for determining the location of oil well casing support. Background Technology

[0002] In oil extraction, the wellbore is the channel through which crude oil is transported from underground to the surface, and it is the most important component of an oil well. Therefore, ensuring that the wellbore is in good condition is the foundation for stable single-well oil and gas production. In recent years, the long-term over-exploitation of groundwater resources in the central Hebei region has led to large-scale surface subsidence, causing casing run-up in oil wells in the area. After the casing runs-up, the hanger comes out, and the hanger assembly, which bears the entire weight of the casing, tubing hanger, and Christmas tree, moves down to the cemented section of the casing well, causing the wellhead to move up and down with the pumping unit and the casing to deform.

[0003] To address this issue, a wellhead lifting and straightening device for oil and water wells, such as application number 201820987413.7, has emerged. This technology can straighten and lift the oil layer casing, transferring the casing support point from the downhole cemented section to the wellhead support device. The support force is then transferred to the surface casing, changing the upward-moving oil layer casing from a compressive state to a tensile state, thus resolving the casing deformation and wellhead movement issues caused by the upward movement of the casing and the pumping unit. In field applications, this technology supports the oil layer casing, ensuring it transitions from a compressive to a tensile state. However, the method for determining the wellhead casing support position is not specified. Failure to accurately determine the wellhead casing support position may lead to the following problems:

[0004] Structural safety risks: If the support force is too large or too small, or the support location is inappropriate, it may cause uneven pressure on the casing structure, leading to casing deformation, rupture, or other structural damage. This not only affects the normal production of the oil well but may also cause serious environmental accidents.

[0005] Equipment failure risk: Improper support settings may subject the suspension assembly and its connecting parts (such as tubing hangers, Christmas trees, etc.) to abnormal stress, increasing the wear rate of these critical components, shortening their service life, or even directly causing equipment failure.

[0006] Decreased production efficiency: Incorrect support positions and force can lead to wellhead instability, preventing the pumping unit from operating smoothly and thus reducing pumping efficiency and impacting single-well oil and gas production. Furthermore, frequent maintenance and repairs can indirectly reduce effective production time.

[0007] Based on this, the present invention proposes a method and apparatus for determining the support position of oil well casing. Summary of the Invention

[0008] To address the aforementioned problems in the prior art, namely, how to determine the location of oil well casing support, this invention provides a method and apparatus for determining the location of oil well casing support.

[0009] In a first aspect, the present invention provides a method for determining the location of an oil well casing support, the method comprising the following steps:

[0010] Step S1: Stop the pumping unit and stop it at the top dead center. Cut off the production pipeline and release the pressure inside the production pipeline. Cut the production pipeline to release stress.

[0011] Step S2: Install the oil well casing support position determination device on the oil wellhead;

[0012] Step S3: Calculate the support force to be applied by the well casing support position determination device based on the weight of the free casing, the weight of the production tubing, and the magnitude of the buoyancy force on the production tubing.

[0013] The oil well casing support position determination device includes a jack, a lifting nut, a load sensor pad, and a lifting cylinder;

[0014] Step S4: Place the two load sensor pads symmetrically on the bottom surface directly below the pipelines on both sides of the main cross-connector of the oil well tree, and place the two jacks on the two load sensor pads respectively, so that the moving end of the jacks is in tight contact with the bottom of the pipelines on both sides of the main cross-connector.

[0015] Step S5: Simultaneously raise both jacks. When the support force displayed on the load sensor pad reaches the support force calculated in step S3, stop raising both jacks.

[0016] Step S6: Rotate the lifting nut to move the lifting cylinder upward until it is tightly pressed against the bottom flange of the large four-way connector, and then re-weld the production pipeline.

[0017] Furthermore, the supporting force F of the lifting and straightening device 承 The calculation method is as follows:

[0018] F 承 =G 自由套管 +G 生产管柱 -F 浮力

[0019] Among them, G 自由套管 G is the weight of the free sleeve. 生产管柱 For the weight of the production tubing, F 浮力 The magnitude of the buoyancy force on the production tubing.

[0020] Furthermore, the weight of the free sleeve is calculated based on the linear density of the free sleeve, the distance from the sleeve neutral point to the cement return height, and the height of the cement return height.

[0021] Furthermore, the weight of the production tubing is calculated based on the product of the linear density of the production tubing and the depth of the production tubing.

[0022] Furthermore, the buoyancy force on the production tubing is calculated based on the density of the produced fluid, the cross-sectional area of ​​the production tubing, the gravitational acceleration, the depth of the production tubing, and the height of the dynamic liquid level.

[0023] Furthermore, after step S6, step S7 is also included: start the pumping unit and observe its operation.

[0024] In a second aspect, the present invention provides an oil well casing support position determination device, based on an oil well casing support position determination method, for straightening a large cross-shaped pipe. The device includes a jack, a lifting nut, a load sensor pad, and a lifting cylinder.

[0025] The top channel and two side channels of the large four-way connector are connected to the production pipeline. The bottom surface of the production pipeline on both sides of the large four-way connector is in contact with the moving end of the jack. The fixed end of the jack is installed on the load sensor pad. The load sensor pad is installed on the ground and is used to display the supporting force applied thereon.

[0026] A lifting cylinder is provided below the bottom surface of the large four-way valve, and the lifting cylinder is used to press the flange of the bottom surface of the large four-way valve tightly;

[0027] The outer surface of the lifting cylinder is threadedly connected to the lifting nut, which is installed above the wellhead.

[0028] Furthermore, the two jacks are symmetrically arranged along the axis of the large cross-connector.

[0029] Furthermore, the large four-way valve is connected to the production pipeline via a valve.

[0030] The beneficial effects of this invention are:

[0031] Precise determination of support position and force: By accurately calculating the weight of the free casing, the weight of the production tubing, and buoyancy, and combining this with real-time monitoring by load sensors during actual operation, the well casing lifting and straightening device can accurately apply the required support force. This method solves the problem of uncertainty in support position and support force in existing technologies, improving the safety and reliability of operations.

[0032] Preventing casing deformation and wellhead movement: The lifting and straightening method of the present invention can effectively change the oil layer casing from a compressed state to a tensile state, avoiding problems such as hanger detachment, casing deformation, and wellhead movement with the pumping unit caused by casing upward movement, thereby ensuring the integrity of the oil well structure.

[0033] Improve maintenance efficiency and reduce risks: By using highly automated jacks and load sensor pads, precise control can be achieved without relying on human experience, reducing the uncertainty caused by human factors, speeding up the maintenance process, and reducing the risks of maintenance operations.

[0034] Extending the service life of oil wells: Properly selecting and applying support points and support forces helps reduce wear between various components of the oil well, protects the internal structure of the wellbore from damage, thereby extending the service life of the oil well and improving the stability of single-well oil and gas production.

[0035] High adaptability: This method is applicable to different types of oil wells, and the parameters can be adjusted according to the specific well conditions, making this solution widely applicable and providing an effective means to deal with oil well problems under complex geological conditions. Attached Figure Description

[0036] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0037] Figure 1 This is a flowchart illustrating a method for determining the location of an oil well casing support according to the present invention.

[0038] Figure 2 This is a schematic diagram of the structure of an oil well casing support position determination device according to the present invention. Detailed Implementation

[0039] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] This invention provides a method for determining the location of oil well casing support, the method comprising the following steps:

[0042] Step S1: Stop the pumping unit and stop it at the top dead center. Cut off the production pipeline and release the pressure inside the production pipeline. Cut the production pipeline to release stress.

[0043] Step S2: Install the oil well casing support position determination device on the oil wellhead;

[0044] Step S3: Calculate the support force to be applied by the well casing support position determination device based on the weight of the free casing, the weight of the production tubing, and the magnitude of the buoyancy force on the production tubing.

[0045] The oil well casing support position determination device includes a jack, a lifting nut, a load sensor pad, and a lifting cylinder;

[0046] Step S4: Place the two load sensor pads symmetrically on the bottom surface directly below the pipelines on both sides of the main cross-connector of the oil well tree, and place the two jacks on the two load sensor pads respectively, so that the moving end of the jacks is in tight contact with the bottom of the pipelines on both sides of the main cross-connector.

[0047] Step S5: Simultaneously raise both jacks. When the support force displayed on the load sensor pad reaches the support force calculated in step S3, stop raising both jacks.

[0048] Step S6: Rotate the lifting nut to move the lifting cylinder upward until it is tightly pressed against the bottom flange of the large four-way connector, and then re-weld the production pipeline.

[0049] To more clearly illustrate the method for determining the location of oil well casing support according to the present invention, the following is in conjunction with... Figure 1 The steps in the embodiments of the present invention will be described in detail below.

[0050] A method for determining the location of an oil well casing support according to a first embodiment of the present invention includes steps S1-S6, each step of which is described in detail below:

[0051] Step S1: Stop the pumping unit and stop it at the top dead center. Cut off the production pipeline and release the pressure inside the production pipeline. Cut the production pipeline to release stress.

[0052] In this embodiment, the pumping unit is stopped at top dead center to ensure safety during operation. Stopping at top dead center (i.e., the highest point of the stroke) reduces the risk to equipment and personnel.

[0053] This invention prevents liquid or gas leaks during subsequent operations by releasing pressure within the pipeline, thus ensuring the safety of personnel. Specifically, this can be achieved by closing relevant valves to isolate the production pipeline and opening the drain port or pressure relief valve to release the pressure within the pipeline.

[0054] This invention can eliminate internal stress in pipelines caused by temperature changes or long-term stress by releasing stress, thus avoiding accidents during cutting or welding.

[0055] Step S2: Install the oil well casing support position determination device on the oil wellhead;

[0056] The oil well casing support position determination device of the present invention includes a jack 3, a lifting nut 4, a load sensor pad 5, and a lifting cylinder 6;

[0057] The top channel and the two side channels of the large four-way connector 2 are connected to the production pipeline 1. The bottom surface of the production pipeline 1 on both sides of the large four-way connector 2 is in contact with the moving end of the jack 3. The fixed end of the jack 3 is installed on the load sensor pad 5. The load sensor pad 5 is installed on the ground and is used to display the supporting force applied thereon.

[0058] A lifting cylinder 6 is provided below the bottom surface of the large four-way 2, and the lifting cylinder 6 is used to press against the flange on the bottom surface of the large four-way 2;

[0059] The outer surface of the lifting cylinder 6 is threadedly connected to the lifting nut 4, which is installed above the wellhead.

[0060] Step S3: Calculate the supporting force applied by the well casing support position determination device based on the weight of the free casing, the weight of the production tubing, and the magnitude of the buoyancy force on the production tubing.

[0061] The supporting force F of the lifting and straightening device 承 The calculation method is as follows:

[0062] F 承 =G 自由套管 +G 生产管柱 -F 浮力 ;

[0063] Among them, G 自由套管 The weight of the free sleeve is expressed in kN (g). 生产管柱 The weight of the production tubing, in kN, F 浮力 The magnitude of the buoyancy force on the production tubing, expressed in kN.

[0064] The weight of the free sleeve is calculated based on the linear density of the free sleeve, the distance from the neutral point of the sleeve to the cement return height, and the height of the cement return height.

[0065] G 自由套管 =ρ 套管 ×(H 水泥返高 -a).

[0066] Where, ρ 套管 Linear density of free sleeve, in units of 10. -3 kN / m, where 'a' is the distance from the neutralization point of the casing to the cement return height, in meters (m), and 'H'. 水泥返高 The height of the cement rise is in meters (m).

[0067] The weight of the production tubing is calculated based on the product of the linear density of the production tubing and the depth of the production tubing.

[0068] G 生产管柱 =ρ 油管 ×H 油管下深 .

[0069] Where, ρ 油管 The linear density of the production tubing, in units of 10. -3 kN / m, depth H of the production tubing 油管下深 The unit is meters (m).

[0070] The buoyancy force on the production tubing is determined by the density ρ of the produced fluid. 采出液 The cross-sectional outer diameter area S of the production tubing 底 Gravitational acceleration g, depth H of the production tubing 油管下深 and the height of the dynamic liquid level H 动液面 The calculation yielded:

[0071] F 浮力 =ρ 采出液 ×g×S 底 ×(H 油管下深 -H 动液面 ).

[0072] Where, ρ 采出液 The density of the produced fluid is expressed in units of 10. 3 kg / m 3 S 底 This refers to the cross-sectional outer diameter area of ​​the production tubing, in units of 10. -6 m 2 g is the acceleration due to gravity, with units of kN / kg, and H 油管下深 The depth of the production tubing, in meters (m), H 动液面 The height of the moving liquid level is expressed in meters (m).

[0073] S 底 =0.25×π×D 2 油管 ;

[0074] Among them, D 油管 This indicates the outer diameter of the production tubing, in units of 10. -3 m.

[0075] Establish a model parameter correspondence table, which is described in Chapter 9, pages 479-484 and 506-507 of the "Well Workover Testing and Production Enhancement Technology Handbook" published by Petroleum Industry Press in April 2009 (first edition). Locate the completion, production, and operation data of the single well to confirm the models of equipment such as tubing and pumps, and then retrieve the parameter values ​​from the above formulas using the model parameter correspondence table.

[0076] The values ​​of each component of the load-bearing capacity are calculated, and the final load-bearing capacity value of the device is obtained through calculation.

[0077] Step S4: Place the two load sensor pads symmetrically on the bottom surface directly below the pipelines on both sides of the main cross-connector of the oil well tree, and place the two jacks on the two load sensor pads respectively, so that the moving end of the jacks is in tight contact with the bottom of the pipelines on both sides of the main cross-connector.

[0078] This invention ensures that the large cross-section and its above structure are uniformly lifted by placing two jacks symmetrically below the production pipelines on both sides of the cross-section and operating them simultaneously. Using only one jack or arranging multiple jacks asymmetrically may result in one side being lifted too high while the other is not lifted enough, causing tilting or instability.

[0079] Each load sensor pad can independently display the support force applied to it, allowing operators to monitor and adjust the force provided by each jack in real time. This precise control is crucial for avoiding over- or under-lifting, ensuring the safety and effectiveness of the jacking process.

[0080] If the force on a jack exceeds the expected value, this anomaly can be detected immediately by the load sensor pad, allowing measures to be taken to prevent potential dangers such as equipment damage or personal injury.

[0081] The load sensor pad not only serves as the foundation for the jack, but also disperses the pressure from the jack, reducing the risk of excessive local pressure on the ground and protecting the ground structure from damage.

[0082] Even if the ground is not perfectly flat, the load sensor pad can be adjusted appropriately (e.g., using a level) to ensure the jack is in a vertical position, thus providing a stable working platform.

[0083] The symmetrical placement design allows operators to flexibly adjust the position and height of the jacks according to the actual situation, ensuring optimal contact points and force distribution.

[0084] When fine-tuning is required, such as to compensate for uneven ground or slight deviations caused by other factors, the symmetrical layout makes calibration simpler and more direct.

[0085] Step S5: Simultaneously raise both jacks. When the support force displayed on the load sensor pad reaches the support force calculated in step S3, stop raising both jacks.

[0086] This invention, by simultaneously raising two jacks, ensures that the large cross-section and its above-ground structure are raised evenly, avoiding tilting or imbalance caused by excessive lifting on one side. This is crucial for maintaining the stability of the wellhead and casing system.

[0087] Synchronous lifting helps to disperse the forces applied to the well structure, reducing the risk of localized stress concentration and thus protecting the wellbore and related equipment from damage.

[0088] Based on the theoretical support force calculated in step S3, the applied support force is ensured to match the expected value by real-time monitoring of the load sensor pad during actual operation. This step guarantees the safety and effectiveness of the jacking process, avoiding potential risks caused by insufficient or excessive support force.

[0089] The lifting stops when the load sensor pad reaches the calculated value, which prevents excessive force from damaging the equipment and also avoids unnecessary energy waste.

[0090] The real-time data provided by the load sensor pad allows operators to understand the current stress situation at any time and make necessary adjustments in a timely manner, such as slowing down the lifting speed or pausing the operation for inspection.

[0091] If the supporting force of a jack increases or decreases abnormally, it can be quickly detected and measures can be taken through the load sensor pad, such as recalibrating the jack position or checking for mechanical faults.

[0092] Step S6: Rotate the lifting nut to move the lifting cylinder upward until it is tightly pressed against the bottom flange of the large four-way connector, and then re-weld the production pipeline.

[0093] This invention uses a rotating lifting nut to move the lifting cylinder upwards and bring it into close contact with the bottom flange of the large cross-junction. This ensures that even if the jack stops applying upward force, the large cross-junction and the structure above it remain in a new, corrected position. This step transforms temporary lifting into permanent position adjustment.

[0094] By transferring the support point of the oil layer casing from the downhole cemented section to the wellhead support device, the casing, which was originally under pressure, is now under tension. This effectively mitigates casing deformation caused by geological subsidence and other factors, protecting the casing and hanger from further damage.

[0095] The tight contact between the lifting cylinder and the large four-way flange surface can prevent the wellhead from moving up and down with the pumping unit, thereby enhancing the stability of the entire system and reducing safety hazards caused by wellhead movement.

[0096] Evenly distributed support helps reduce the risk of localized stress concentration, thereby extending the service life of equipment and wellbore structures.

[0097] Re-welding production pipelines is essential to restore the normal production function of oil wells and ensure the smooth transport of crude oil or natural gas from underground to the surface. Strict adherence to standard operating procedures is required during the welding process to guarantee the sealing and strength of the joints.

[0098] High-quality welding not only restored the functionality of the production pipeline, but also ensured its long-term reliability and safety, preventing future leaks or other malfunctions.

[0099] Step S6 is followed by step S7, which involves starting the pumping unit and observing its operation.

[0100] The application of this invention will be described in detail below with reference to a specific embodiment of the Ze 10-47 well. Figure 2 This can be used as a structural schematic diagram of this embodiment.

[0101] Well Ze 10-47:

[0102] Step S1: Stop the pumping unit and stop it at the top dead center. Cut off the production pipeline and release the pressure inside the production pipeline. Cut the production pipeline to release stress.

[0103] Step S2: Install the oil well casing support position determination device on the oil wellhead;

[0104] Step S3: Calculate the supporting force applied by the well casing support position determination device based on the weight of the free casing, the weight of the production tubing, and the magnitude of the buoyancy force on the production tubing.

[0105] Based on the well parameters, the support load values ​​for this well were calculated as follows: the well's casing steel grade is N80, with a specification of 139.7mm, wall thickness of 7.72mm, inner diameter of 124.26mm, and tubing diameter of D73mm. According to the model parameter correspondence table, ρ_casing = 248, ρ_tubing = 95, S_section - tubing = 1169. Based on single-well data, H_tubing depth = 2093.3, H_cement return height = 1295, H_dynamic fluid level = 1832, ρ_produced fluid = 0.97. Calculations using the formula yielded G_casing = 197.2, G_tubing = 198.9, S_bottom - tubing = 0.0042, F_buoyancy = 10.4, and F_support = 385.7.

[0106] Step S4: Place two weighted sensor pads on the ground below the horizontal direction of the main cross-section of the oil well tree, and place the jack on the load sensor pads, with the top of the jack in close contact with the bottom of the pipelines on both sides of the main cross-section.

[0107] Step S5: Simultaneously raise both jacks. Once the support force displayed on the load sensor pad reaches the calculated value, stop raising both jacks.

[0108] Step S6: Rotate the lifting nut of the wellhead lifting and straightening device to move the lifting cylinder upward until it is pressed against the bottom flange face of the large four-way connector. The displacement after support is the determined support position; weld the production pipeline.

[0109] Step S7: Start pumping and observe the operation of the pumping unit.

[0110] After the operation, the original "flagpole" swaying phenomenon of the well casing was changed. Generally, the fixing device needs to be re-fixed every two to six months. By applying the method of this invention to determine the bearing capacity value, the wellhead remained normal and stable for two years after implementation, and the construction was successful.

[0111] See Figure 2 The second embodiment of the present invention proposes an oil well casing support position determination device, based on an oil well casing support position determination method of the first embodiment, for straightening the large four-way valve 2. The device includes a jack 3, a lifting nut 4, a load sensor pad 5, and a lifting cylinder 6.

[0112] The top channel and the two side channels of the large four-way connector 2 are connected to the production pipeline 1. The bottom surface of the production pipeline 1 on both sides of the large four-way connector 2 is in contact with the moving end of the jack 3. The fixed end of the jack 3 is installed on the load sensor pad 5. The load sensor pad 5 is installed on the ground and is used to display the supporting force applied thereon.

[0113] A lifting cylinder 6 is provided below the bottom surface of the large four-way 2, and the lifting cylinder 6 is used to press against the flange on the bottom surface of the large four-way 2;

[0114] The outer surface of the lifting cylinder 6 is threadedly connected to the lifting nut 4, which is installed above the wellhead.

[0115] As a further explanation of the present invention, the two jacks 3 are symmetrically arranged along the axis of the large four-way connector 2.

[0116] As a further explanation of the present invention, the large four-way valve 2 is connected to the production pipeline 1 via a valve.

[0117] Although the steps in the above embodiments are described in the above order, those skilled in the art will understand that in order to achieve the effect of this embodiment, different steps do not need to be executed in such an order. They can be executed simultaneously (in parallel) or in a reverse order. These simple variations are all within the protection scope of this invention.

[0118] The terms “first”, “second”, etc., are used to distinguish similar objects, not to describe or indicate a specific order or sequence.

[0119] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0120] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for determining the location of an oil well casing support, characterized in that, The method includes the following steps: Step S1: Stop the pumping unit and stop it at the top dead center. Cut off the production pipeline and release the pressure inside the production pipeline. Cut the production pipeline to release stress. Step S2: Install the oil well casing support position determination device on the oil wellhead; Step S3: Calculate the support force to be applied by the well casing support position determination device based on the weight of the free casing, the weight of the production tubing, and the magnitude of the buoyancy force on the production tubing. The oil well casing support position determination device includes a jack, a lifting nut, a load sensor pad, and a lifting cylinder; Step S4: Place the two load sensor pads symmetrically on the bottom surface directly below the pipelines on both sides of the main cross-connector of the oil well tree, and place the two jacks on the two load sensor pads respectively, so that the moving end of the jacks is in tight contact with the bottom of the pipelines on both sides of the main cross-connector. Step S5: Simultaneously raise both jacks. When the support force displayed on the load sensor pad reaches the support force calculated in step S3, stop raising both jacks. Step S6: Rotate the lifting nut to move the lifting cylinder upward until it is tightly pressed against the bottom flange of the large four-way connector, and then re-weld the production pipeline.

2. The method for determining the location of oil well casing support according to claim 1, characterized in that, The supporting force F of the lifting and straightening device 承 The calculation method is as follows: F 承 =G 自由套管 +G 生产管柱 -F 浮力 ; Among them, G 自由套管 G is the weight of the free sleeve. 生产管柱 For the weight of the production tubing, F 浮力 The magnitude of the buoyancy force on the production tubing.

3. The method for determining the location of oil well casing support according to claim 2, characterized in that, The weight of the free sleeve is calculated based on the linear density of the free sleeve, the distance from the neutral point of the sleeve to the cement return height, and the height of the cement return height.

4. The method for determining the location of oil well casing support according to claim 2, characterized in that, The weight of the production tubing is calculated based on the product of the linear density of the production tubing and the depth of the production tubing.

5. The method for determining the location of oil well casing support according to claim 2, characterized in that, The buoyancy force on the production tubing is calculated based on the density of the produced fluid, the cross-sectional area of ​​the production tubing, the gravitational acceleration, the depth of the production tubing, and the height of the dynamic liquid level.

6. The method for determining the location of oil well casing support according to claim 1, characterized in that, Step S6 is followed by step S7, which involves starting the pumping unit and observing its operation.

7. A device for determining the position of an oil well casing support, based on the method for determining the position of an oil well casing support according to any one of claims 1-6, used for straightening a large cross-junction, characterized in that, The device includes a jack, a lifting nut, a load sensor pad, and a lifting cylinder; The top channel and two side channels of the large four-way connector are connected to the production pipeline. The bottom surface of the production pipeline on both sides of the large four-way connector is in contact with the moving end of the jack. The fixed end of the jack is installed on the load sensor pad. The load sensor pad is installed on the ground and is used to display the supporting force applied thereon. A lifting cylinder is provided below the bottom surface of the large four-way valve, and the lifting cylinder is used to press the flange of the bottom surface of the large four-way valve tightly; The outer surface of the lifting cylinder is threadedly connected to the lifting nut, which is installed above the wellhead.

8. The oil well casing support position determination device according to claim 7, characterized in that, The two jacks are symmetrically arranged along the axis of the large cross-connector.

9. The oil well casing support position determination device according to claim 7, characterized in that, The large four-way valve is connected to the production pipeline via a valve.

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